diff --git a/.vscodeignore b/.vscodeignore
index c06f4a7..34606f3 100644
--- a/.vscodeignore
+++ b/.vscodeignore
@@ -1,10 +1,13 @@
 .vscode/**
 .vscode-test/**
 out/test/**
 src/**
 .gitignore
 vsc-extension-quickstart.md
 **/tsconfig.json
 **/.eslintrc.json
 **/*.map
 **/*.ts
+NOTES
+.arc*
+
diff --git a/src/extension.ts b/src/extension.ts
index 035e29c..508440a 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -1,123 +1,165 @@
 import * as vscode from 'vscode';
 import * as execa from "execa";
 import * as path from "path";
 
 
 export function activate(context: vscode.ExtensionContext) {
 	const collection = vscode.languages.createDiagnosticCollection('arc lint');
-	if (vscode.window.activeTextEditor) {
-		lintFile(vscode.window.activeTextEditor.document);
-	}
+
+	setupCustomTranslators();
 
 	function d(disposable: vscode.Disposable) {
 		context.subscriptions.push(disposable);
 	}
 
 	d(vscode.commands.registerCommand('arc-vscode.clearLint', () => collection.clear()));
 
 	d(vscode.workspace.onDidSaveTextDocument(onTextDocumentEvent));
 	d(vscode.workspace.onDidOpenTextDocument(onTextDocumentEvent));
 
+	if (vscode.window.activeTextEditor) {
+		lintFile(vscode.window.activeTextEditor.document);
+	}
+
 	d(vscode.window.onDidChangeActiveTextEditor(editor => {
 		if (editor) {
 			lintFile(editor.document);
 		}
 	}));
 
 	function onTextDocumentEvent(document: vscode.TextDocument) {
 		lintFile(document);
 	}
 
 	function lintFile(document: vscode.TextDocument) {
 		if (document.uri.scheme != "file") return;
 
 		function handleExecResult(value: execa.ExecaReturnValue<string>) {
+			//! this function throws and then we ignore if the lint actually broke.
+			if (!value.stdout)
+				return;
+
 			const lintMessages = JSON.parse(value.stdout);
 
 			for (const filename in lintMessages) {
 				// TODO: This only probably works because we call arc with a single file.
 				collection.set(document.uri, lintJsonToDiagnostics(lintMessages[filename]));
 			}
 		}
 
 		const filename = document.uri.path;
 
 		execa(
 			'arc', ['lint', '--output', 'json', '--', path.basename(filename)],
 			{ cwd: path.dirname(filename) },
 		).then(handleExecResult, handleExecResult);
 	}
 
 }
 
 export function deactivate() { }
 
 function logError(x: any) {
 	console.log("this is error", x);
 }
 
+type LintTranslator = (lint: any) => vscode.Diagnostic;
+let customLintTranslator: Map<String, LintTranslator> = new Map();
+
 function lintJsonToDiagnostics(lintResults: Array<any>): vscode.Diagnostic[] {
 	/*
 	input: Array of:
  		{
             "line": 248,
             "char": 23,
             "code": "SPELL1",
             "severity": "warning",
             "name": "Possible Spelling Mistake",
             "description": "Possible spelling error. You wrote 'seperator', but did you mean 'separator'?",
             "original": "Seperator",
             "replacement": "Separator",
             "granularity": 1,
             "locations": [],
             "bypassChangedLineFiltering": null,
             "context": "    magic = COLOR_RED;\n    break;\n  case 30:\n    // printf(\"Record Seperator\");\n    magic = COLOR_BLUE;\n    break;\n  case 31:"
         }
 	output: array of:
 		{
 			code: '',
 			message: 'cannot assign twice to immutable variable `x`',
 			range: new vscode.Range(new vscode.Position(3, 4), new vscode.Position(3, 10)),
 			severity: vscode.DiagnosticSeverity.Error,
 			source: '',
 			relatedInformation: [
 				new vscode.DiagnosticRelatedInformation(new vscode.Location(document.uri, new vscode.Range(new vscode.Position(1, 8), new vscode.Position(1, 9))), 'first assignment to `x`')
 			]
 		}
 	*/
 
 	/*
 		Extra features:
 		- quick-fix to apply patch
 		- try to get better message by parsing `description` field (per message code...)
 		- `locations` may be parsed into `relatedInformation`.
 	*/
 
-	function message(lint: any) {
-		if (lint.description)
-			return lint.name + ": " + lint.description
-		return lint.name
-	}
 
-	function severity(lint: any): vscode.DiagnosticSeverity {
-		switch (lint.severity as string) {
-			case 'disabled': return vscode.DiagnosticSeverity.Hint;
-			case 'autofix': return vscode.DiagnosticSeverity.Hint;
-			case 'advice': return vscode.DiagnosticSeverity.Information;
-			case 'warning': return vscode.DiagnosticSeverity.Warning;
-			case 'error': return vscode.DiagnosticSeverity.Error;
-			default: return vscode.DiagnosticSeverity.Error;
-		}
+
+
+	function translate(lint: any): vscode.Diagnostic {
+		let t = customLintTranslator.get(lint.code) || defaultTranslate;
+		return t(lint);
 	}
 
+	return lintResults.map(translate);
+}
+
+function nonNeg(n: number): number {
+	if (n < 0) return 0
+	return n
+}
+
+function defaultTranslate(lint: any): vscode.Diagnostic {
+	return {
+		code: lint.code,
+		message: message(lint),
+		severity: severity(lint),
+		source: 'arc lint',
+		range: new vscode.Range(
+			lint.line - 1, nonNeg(lint.char - 2), // it's an artificial 3-chars wide thing.
+			lint.line - 1, lint.char + 1),
+	};
+}
+function message(lint: any) {
+	if (lint.description)
+		return lint.name + ": " + lint.description
+	return lint.name
+}
+
+function severity(lint: any): vscode.DiagnosticSeverity {
+	switch (lint.severity as string) {
+		case 'disabled': return vscode.DiagnosticSeverity.Hint;
+		case 'autofix': return vscode.DiagnosticSeverity.Hint;
+		case 'advice': return vscode.DiagnosticSeverity.Information;
+		case 'warning': return vscode.DiagnosticSeverity.Warning;
+		case 'error': return vscode.DiagnosticSeverity.Error;
+		default: return vscode.DiagnosticSeverity.Error;
+	}
+}
+function setupCustomTranslators() {
+	customLintTranslator.set("SPELL1",
+		lint => {
+			let d = defaultTranslate(lint)
+
+			d.message = lint.description;
+			let len = (<String>lint.original).length;
+			if (len > 0) {
+				d.range = new vscode.Range(
+					lint.line - 1, nonNeg(lint.char - 1),
+					lint.line - 1, lint.char + len - 1);
+			}
 
-	return lintResults.map(lint => {
-		return {
-			code: lint.code,
-			message: message(lint),
-			severity: severity(lint),
-			source: 'arc lint',
-			range: new vscode.Range(lint.line - 1, 0, lint.line - 1, 1e9),
+			return d
 		}
-	})
+	);
 }